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Abstract:

A light-emitting device includes a substrate having a front surface on
which a semiconductor light-emitting element is mounted. A front cover is
provided which thermally contacts the front surface of the substrate at a
periphery of the semiconductor light-emitting element and is disposed on
a front side of the substrate. A heat conduction path is formed along
which heat generated by the semiconductor light-emitting element is
conducted in order of the substrate and the front cover and the heat is
radiated from a front surface of the front cover, so that a heat
radiation property from a front surface of the light-emitting device is
improved.

Claims:

1. A light-emitting device comprising: a substrate including a front
surface on which a semiconductor light-emitting element is mounted; and a
front cover that thermally contacts the front surface of the substrate at
a periphery of the semiconductor light-emitting element and is disposed
on a front side of the substrate.

2. The device of claim 1, wherein the front cover is in close contact
with the front surface of the substrate and the semiconductor
light-emitting element.

3. The device of claim 1, wherein a wiring patter to which the
semiconductor light-emitting element is electrically connected is
provided on the front surface of the substrate, and the front cover
thermally contacts the wiring pattern.

4. The device of claim 3, wherein the wiring pattern provided on the
front surface of the substrate includes a mounting pad on which the
semiconductor light-emitting element is mounted, the front cover includes
an air layer forming unit that covers the semiconductor light-emitting
element and faces the semiconductor light-emitting element, and a heat
conduction layer is provided between the front surface of the substrate
and an area of the front cover except for the air layer forming unit, and
contacts the mounting pad.

5. The device of claim 4, wherein the heat conduction layer has
adhesiveness.

6. The device of claim 1, wherein a nano-fine particle coating is
provided on the front surface of the front cover.

7. A light-emitting device comprising: a front cover including a back
surface on which a wiring pattern is provided; and a semiconductor
light-emitting element that is disposed on a back side of the front
cover, and is electrically and thermally connected to the wiring pattern
of the front cover.

8. A lighting apparatus comprising: an apparatus body; and a
light-emitting device of claim 1 disposed on the apparatus body.

9. The device of claim 2, wherein a nano-fine particle coating is
provided on the front surface of the front cover.

10. The device of claim 3, wherein a nano-fine particle coating is
provided on the front surface of the front cover.

11. The device of claim 4, wherein a nano-fine particle coating is
provided on the front surface of the front cover.

12. The device of claim 5, wherein a nano-fine particle coating is
provided on the front surface of the front cover.

13. A lighting apparatus comprising: an apparatus body; and a
light-emitting device of claim 2 disposed on the apparatus body.

14. A lighting apparatus comprising: an apparatus body; and a
light-emitting device of claim 3 disposed on the apparatus body.

15. A lighting apparatus comprising: an apparatus body; and a
light-emitting device of claim 4 disposed on the apparatus body.

16. A lighting apparatus comprising: an apparatus body; and a
light-emitting device of claim 5 disposed on the apparatus body.

17. A lighting apparatus comprising: an apparatus body; and a
light-emitting device of claim 6 disposed on the apparatus body.

18. A lighting apparatus comprising: an apparatus body; and a
light-emitting device of claim 7 disposed on the apparatus body.

Description:

FIELD

[0001] Embodiments described herein relate generally to a light-emitting
device using a semiconductor light-emitting element and a lighting
apparatus using the light-emitting device.

BACKGROUND

[0002] Hitherto, a light-emitting device using, for example, an LED
element as a semiconductor light-emitting element includes a substrate
having a front surface on which a wiring pattern is formed, plural LED
elements mounted on the wiring pattern of the front surface of the
substrate, a lens that is arranged on the front surface of the substrate
and controls the light emitted from the respective LED elements.

[0003] In the light-emitting device as stated above, generally, heat
generated by the LED elements is conducted to the substrate, and is
radiated from the back surface of the substrate to a lighting equipment
on which the substrate is mounted, and the reduction of the light output
of the LED element and the reduction of the life thereof are suppressed.

[0004] However, in the light-emitting device having the structure in which
heat is radiated from the back surface of the substrate, if the
light-emitting device is used for a ceiling mounting type lighting
equipment, although heat is conducted from the back surface of the
substrate to a top plate of an equipment body, a material hard to conduct
heat, such as gypsum board or wood, is often used for the ceiling member
to which the top plate of the equipment body is attached, and a required
heat radiation property may not be secured from the top plate of the
equipment body. Thus, a countermeasure such as to form a gap between the
top plate of the equipment body and the ceiling member is required, which
prevents reduction of the thickness of the lighting equipment.

[0005] Besides, there is a light-emitting device in which the area of a
wiring pattern formed on the front surface of a substrate is made wide,
heat generated by LED elements is conducted to the wiring pattern having
the wide area, and the heat is radiated to the air from the wiring
pattern, so that the heat radiation property from the front surface of
the substrate is also secured.

[0006] Besides, there is a light-emitting device in which a substrate on
which plural LED elements are mounted is arranged inside a housing,
plural spacers are provided between the housing and the front surface of
the substrate, and the substrate is fixed to the housing by screws
inserted in the respective spacers. In this light-emitting device, heat
generated by the LED elements is conducted to the substrate, is conducted
from the substrate to the housing through the spacers and the screws, and
is radiated from the housing.

CITATION LIST

Patent Literature

[0007] [PTL 1] JP-A-2004-335880 [0008] [PTL 2] JP-A-2008-130823

SUMMARY OF INVENTION

Technical Problem

[0009] However, in the light-emitting device having the structure in which
heat is radiated to the air from the wiring pattern on the front surface
of the substrate, the lens and the like are arranged on the front surface
side of the substrate, and sufficient air convection can not be obtained
at the front surface side of the substrate, and therefore, there is a
problem that a sufficient heat radiation property can not be secured.

[0010] Besides, in the light-emitting device in which heat is radiated by
heat conduction from the front surface of the substrate to the housing, a
place where heat is conducted from the front surface of the substrate to
the housing is only the place of the spacers and the screws, and an air
layer as a heat insulating layer is provided between the front surface of
the substrate and the housing, except for the place of the spacers and
the screws. Therefore, sufficient heat conductivity from the front
surface of the substrate to the housing can not be obtained, and there is
a problem that a sufficient heat radiation property from the front
surface of the light-emitting device can not be secured.

[0011] The invention is made in view of such circumstances, and an object
thereof is to provide a light-emitting device and a lighting apparatus,
in which a sufficient heat radiation property from a front surface can be
secured.

Solution to Problem

[0012] In general, according to one embodiment, a light-emitting device
includes a substrate having a front surface on which a semiconductor
light-emitting element is mounted. A front cover is provided which
thermally contacts the front surface of the substrate at a periphery of
the semiconductor light-emitting element and is disposed on a front side
of the substrate. A heat conduction path is formed along which heat
generated by the semiconductor light-emitting element is conducted in
order of the substrate and the front cover and the heat is radiated from
a front surface of the front cover, so that a heat radiation property
from the front surface of the light-emitting device is improved.

BRIEF DESCRIPTION OF THE DRWAINGS

[0013] FIGS. 1(a) and 1(b) show a first embodiment, in which

[0014]FIG. 1(a) is a sectional view of a part of a light-emitting device,
and FIG. 1(b) is an enlarged sectional view of a part of the
light-emitting device.

[0016]FIG. 3 is a perspective view of an exploded state of the
light-emitting device.

[0017]FIG. 4 shows a second embodiment and is a sectional view of a part
of a light-emitting device.

[0018] FIGS. 5(a) and 5(b) show a temperature distribution in which
semiconductor light-emitting elements of the light-emitting device are
lighted and temperature is measured, in which FIG. 5(a) is a temperature
distribution view of a case where an air layer exists in a front cover,
and FIG. 5(b) is a temperature distribution view of a case where an air
layer does not exist in the front cover.

[0019]FIG. 6 shows a third embodiment and is a sectional view of a part
of a light-emitting device.

[0020]FIG. 7 is a table showing a summary of results obtained by
measuring temperature of a semiconductor light-emitting element while
changing conditions of a front cover of the light-emitting device.

[0021]FIG. 8 shows a fourth embodiment and is a sectional view of a part
of a light-emitting device.

[0022]FIG. 9 shows a fifth embodiment and is a sectional view of a part
of a light-emitting device.

[0023]FIG. 10 shows a sixth embodiment and is a perspective view of a
light-emitting device.

[0024]FIG. 11 is a sectional view of the light-emitting device taken
along A-A of FIG. 10.

[0025]FIG. 12 is a sectional view in which a part of the light-emitting
device of FIG. 11 is enlarged.

[0026]FIG. 13 is a plan view of a front cover of the light-emitting
device.

[0027]FIG. 14 is a front view showing a wiring pattern of a substrate of
the light-emitting device.

[0028]FIG. 15 is a front view showing a state in which light-emitting
elements are mounted on the wiring pattern of the substrate of the
light-emitting device and phosphor layers are coated.

[0029]FIG. 16 is a sectional view showing a process in which the
substrate of the light-emitting device and the front cover are combined
and are bonded by a heat conduction layer.

[0030]FIG. 17 is a front view showing a state in which the substrate of
the light-emitting device and the front cover are combined.

[0031]FIG. 18 is a sectional view showing a relation between an opening
part of an air layer forming unit and a mounting pad when the
light-emitting device is seen from a front direction.

[0032]FIG. 19 is a side view of a lighting apparatus using the
light-emitting device.

[0033]FIG. 20 is a front view in which the lighting apparatus is seen
from a light irradiation direction.

[0034]FIG. 21 shows a seventh embodiment and is a perspective view of a
lighting apparatus.

[0035]FIG. 22 shows an eighth embodiment and is a sectional view in which
a part of a light-emitting device is enlarged.

[0036]FIG. 23 shows a ninth embodiment and is a sectional view showing a
relation between an opening part of an air layer forming unit and a
mounting pad, in which a light-emitting device is seen from a front
direction.

[0037]FIG. 24 shows a tenth embodiment and is a sectional view in which a
part of a light-emitting device is enlarged.

[0038]FIG. 25 shows an eleventh embodiment and is a sectional view in
which a part of a light-emitting device is enlarged.

[0039]FIG. 26 shows a twelfth embodiment and is a sectional view of a
light-emitting device.

DETAILED DESCRIPTION

[0040] Hereinafter, a first embodiment will be described with reference to
FIG. 1 to FIG. 3.

[0041] A light-emitting device 11 includes a substrate 13 including a
front surface 13a as a mounting surface on which plural semiconductor
light-emitting elements 12 are mounted, and a front cover 14 disposed so
as to cover the front surface 13a of the substrate 13.

[0042] The semiconductor light-emitting element 12 is, for example, an LED
element, and an SMD (Surface Mount Device) type is used in which a
light-emitting element includes a terminal mounted with an LED chip. That
is, the semiconductor light-emitting element 12 includes a square base
having a terminal 12a as a lead terminal, an LED chip that is mounted on
the base, is electrically connected to the terminal 12a and emits blue
light, a reflector that houses the LED chip and reflects the light
emitted by the LED chip forward, and a phosphor layer as a transparent
resin that covers the LED chip in the reflector and is mixed with a
phosphor which is excited by the blue light emitted by the LED chip and
mainly emits yellow light. The semiconductor light-emitting element 12 is
constructed such that the LED chip is a primary light source, the front
surface of the phosphor layer as a planar secondary light source is a
light-emitting surface, and white light is emitted from the
light-emitting surface.

[0043] The substrate 13 includes a substrate body 21 made of a metal, such
as aluminum, excellent in heat conductivity or a non-metal material, and
formed into a square shape. As the non-metal material of the substrate
body 21, for example, ceramics is used, or a glass epoxy substrate, a
paper phenol substrate or the like is used, and a horizontally
anisotropic heat conducting substrate may be used. An insulating layer 22
is formed on the front surface of the substrate body 21, and a wiring
pattern 23 as a wiring layer for connecting the plural semiconductor
light-emitting elements 12 in series is formed on the insulating layer
22. Further, a resist layer 24 flush with the wiring pattern 23 is formed
in an area where the wiring layer pattern 23 is not formed. The wiring
pattern 23 is formed of a copper foil or the like excellent in heat
conductivity. Since the heat conduction efficiency from the semiconductor
light-emitting element 12 to the front cover 14 is high, the non-metal
material can be used as the material of the substrate body 21.

[0044] The plural semiconductor light-emitting elements 12 are arranged on
the wiring pattern 23 of the substrate 13 at regular intervals in
horizontal and vertical directions of the substrate 13, and the terminal
12a of each of the semiconductor light-emitting elements 12 is
electrically connected to the wiring pattern 23 by a solder 25 and is
mounted.

[0045] Besides, aback surface 14b of the front cover 14 is formed as a
contact surface that thermally contacts the front surface 13a of the
substrate 13 at the periphery of the semiconductor light-emitting element
12. That the front cover 14 thermally contacts the front surface of the
substrate 13 means a state where surface contact is performed without
forming an intervening air layer or the like, and high heat conductivity
is secured. Incidentally, although the back surface 14b of the front
cover 14 preferably contacts the front surface 13a of the substrate 13 so
as to surround the periphery of the semiconductor light-emitting element
12, if the heat conductivity is secured, a mode of contact with a part of
the periphery may be adopted.

[0046] The front cover 14 includes a reflecting member 31 as a first cover
member and a translucent member 32 as a second cover member, and plural
light emitting parts 33 are formed correspondingly to positions of the
respective semiconductor light-emitting elements 12 mounted on the
substrate 13.

[0047] The reflecting member 31 is integrally molded into a square shape
similarly to the substrate 13. Square opening parts 34 in which the
respective semiconductor light-emitting elements 12 are inserted and
arranged are formed correspondingly to the positions of the respective
semiconductor light-emitting elements 12 mounted on the substrate 13,
that is, at the respective light emitting parts 33. A
quadrangular-pyramid-shaped recess 35 is formed to expand and open
forward from each of the opening parts 34. The inner surface of the
recess 35 is formed as a reflecting surface to reflect the light emitted
by the semiconductor light-emitting element 12 forward. The back surface
of the reflecting member 31 is brought into surface contact with the
substrate 13 without forming an air layer by using a heat conduction
layer (similar to a heat conduction layer 52 described in a sixth
embodiment) of, for example, epoxy adhesive and close contact is
realized, so that the reflecting member is bonded and fixed in a thermal
contact state. Incidentally, the back surface of the reflecting member 31
may be brought into surface contact with the front surface 13a of the
substrate 13 without forming an air layer by using mechanical means such
as screwing and close contact may be realized, so that the reflecting
member is fixed in the thermal contact state.

[0048] The translucent member 32 is formed by filling each of the recesses
35 of the reflecting members 31 fixed to the substrate 13 with a
transparent resin, and is brought into direct surface contact with the
substrate 13, the semiconductor light-emitting element 12 and the inside
of the recess 35 of the reflecting member 31 without forming an air layer
and close contact is realized, so that thermal contact is realized. A
front surface of the translucent member 32 is formed as a light emitting
surface from which the light emitted by the semiconductor light-emitting
element 12 outgoes.

[0049] The reflecting member 31 and the translucent member 32 are formed
of transparent resins that have a high heat conductivity of about 1 to 5
W/mk and a transmittance of 90% or more for light having a wavelength of,
for example, 400 to 800 nm, and are different in refractive index. For
example, the reflecting member 31 is formed of a high refractive index
resin having high heat conductivity, such as epoxy resin kneaded with
carbon, acryl resin, polycarbonate or polyphenylene sulfide (PPS).
Besides, the translucent member 32 is formed of a low refractive index
resin such as silicone resin. Incidentally, the heat conductivity of the
air layer is about 0.01 to 0.02 W/mk, and the heat conductivity of common
resin is about 0.2 W/mk.

[0050] The reflecting surface 36 to reflect light is formed at the
interface between the reflecting member 31 and the translucent member 32
that are different in refractive index. The reflective index is set by
setting the difference in refractive index, and various light
distribution controls can be performed without changing the shape.

[0051] Incidentally, although the reflecting member 31 preferably has a
high heat conductivity, this is not a necessary condition. This is
because, with respect to the reflecting member 31, to secure the size of
the contact area with the front surface 13a of the substrate 13 and the
heat radiation area exposed forward is a more important design element in
raising the heat radiation property. Further, the reflecting member 31
may be transparent or opaque, or a metal material may be used if an
insulating layer intervenes between the reflecting member and the front
surface 13a of the substrate 13.

[0052] Besides, a nano-fine particle coating 37 is applied to a front
surface 14a of the front cover 14. The nano-fine particle coating 37 has
high heat conductivity and heat radiation property, is made of inorganic
fine particles of, for example, Al2O3 or TiO2, which are
fine particles having an average particle diameter of 30 to 50 nm and
preferably having a particle distribution with a peak of about 40 nm, and
a film thickness thereof is 100 to 200 nm. Further, the nano-fine
particle coating 37 has a light diffusion property, and can diffuse the
light emitted from the semiconductor light-emitting element 12.
Incidentally, if the front cover 14 has high heat radiation function, the
nano-fine particle coating 37 may be omitted.

[0053] Next, the operation of the light-emitting device 11 will be
described.

[0054] Power is supplied to the respective semiconductor light-emitting
elements 12 through the wiring pattern 23 of the substrate 13, so that
the respective semiconductor light-emitting elements 12 emit white light,
and the light passes through the translucent member 32 of the front cover
14, and is emitted forward from the front surface 14a.

[0055] Part of the heat generated by the respective lighted semiconductor
light-emitting elements 12 is conducted to the substrate 13 and is
conducted from the substrate 13 to the reflecting member 31 of the front
cover 14. Besides, part of the heat is conducted to the translucent
member 32 of the front cover 14, and the heat is radiated into the front
air in the same direction as the light irradiation direction from the
front surface 14a of the front cover 14 as the front surface of the
reflecting member 31 and the translucent member 32.

[0056] At this time, the heat generated by the respective lighted
semiconductor light-emitting elements 12 is mainly efficiently conducted
to the substrate 13 on which the semiconductor light-emitting elements 12
are mounted, and is particularly conducted very efficiently from the
terminals 12a, which are excellent in heat conductivity, of the
semiconductor light-emitting elements 12 to the wiring pattern 23 of the
substrate 13. The heat conducted to the substrate 13 extends along the
substrate 13, is efficiently conducted from the front surface 13a of the
substrate 13, which is formed to be flush and has a relatively large
area, to the front cover 14 which is in close contact by surface contact
without an air layer so that thermal contact is realized, and the heat is
radiated to the air from the front surface 14a of the front cover 14,
which has a large area and is exposed forward.

[0057] As stated above, in the light-emitting device 11, since the front
cover 14 disposed on the front surface 13a of the substrate 13 thermally
contacts the front surface 13a of the substrate 13 at the periphery of
the semiconductor light-emitting element 12, a heat conduction path is
formed such that the heat generated by the semiconductor light-emitting
element 12 is efficiently conducted in order of the substrate 13 and the
front cover 14 and is radiated from the front surface 14a of the front
cover 14, and the heat radiation property from the front surface of the
light-emitting device 11 can be improved.

[0058] Especially, since the front cover 14 is indirect surface contact
with the front surface 13a of the substrate 13 and the semiconductor
light-emitting element 12 and close contact is realized, an air layer
does not intervene between these, the heat conduction efficiency from the
substrate 13 and the semiconductor light-emitting element 12 to the front
cover 14 is high, and the heat radiation property from the front surface
of the light-emitting device 11 can be improved.

[0059] Further, since the front cover 14 thermally contacts the wiring
pattern 23 formed on the front surface 13a of the substrate 13, the heat
of the semiconductor light-emitting element 12 is conducted to the front
cover 14 through the terminal 12a and through the wiring pattern 23 where
heat is efficiently conducted. Accordingly, the heat conduction
efficiency is high, and the heat radiation property from the front
surface of the light-emitting device 11 can be improved. Incidentally,
since the resist layer 24 is further formed on the front surface of the
wiring pattern 23, the heat is conducted to the front cover 14 through
the resist layer 24.

[0060] Besides, since the nano-fine particle coating 37 having high heat
conductivity and heat radiation property is applied to the front surface
14a of the front cover 14, the heat radiation property from the front
surface of the light-emitting device 11 can be improved.

[0061] The light-emitting device 11 constructed as stated above can be
applied to a lighting apparatus, for example, a ceiling mounting lighting
equipment. When the light-emitting device is applied to the ceiling
mounting lighting equipment, the back surface of the light-emitting
device 11 is attached to the lower surface of a top plate of an apparatus
body attached to a ceiling member. However, even if a material hard to
conduct heat, such as gypsum board or wood, is used as the ceiling member
to which the top plate of the apparatus body is attached, and a
sufficient heat radiation property can not be secured by the top plate of
the apparatus body, a heat radiation property sufficient to suppress
reduction of light output of the semiconductor light-emitting element 12
and reduction of life thereof can be secured by the front surface of the
light-emitting device 11. Accordingly, countermeasures such as to form a
gap between the top plate of the apparatus body and the ceiling member
are not required, and the lighting apparatus can be made thin.
Incidentally, a specific example of the lighting apparatus will be
described later.

[0062]FIG. 4 and FIGS. 5(a) and 5(b) show a second embodiment.
Incidentally, the same component as that of the foregoing embodiment is
denoted by the same reference numeral and its description is omitted.

[0063] As shown in FIG. 4, a light-emitting device 11 is such that in the
light-emitting device 11 of the first embodiment shown in FIG. 1 to FIG.
3, the translucent member 32 of the front cover 14 is formed of soft
silicone resin, and for the purpose of protecting the translucent member
32, the front cover 14 includes a transparent cover 41 to integrally
cover the whole of the reflecting member 31 and the translucent member
32. The cover 41 is formed of a transparent resin having a transmittance
of 90% or more for light having a wavelength of, for example, 400 to 800
nm, and is brought into surface contact with the front surface of the
reflecting member 31 and the translucent member 32 without forming an air
layer and close contact is realized, so that the cover is attached
thereto in a thermal contact state. A nano-fine particle coating 37 is
formed on the front surface of the cover 41 as the front surface 14a of
the front cover 14.

[0064] Besides, FIGS. 5(a) and 5(b) are views showing temperature
distribution which is obtained by lighting the semiconductor
light-emitting elements 12 of the light-emitting device 11 and measuring
the temperature. FIG. 5(a) shows a case where an air layer exists in the
front cover 14, that is, the translucent member 32 is not formed in the
recess 35 of the reflecting member 31 of the front cover 14, and the air
layer exists in the front cover 14 and in a space surrounded by the
substrate 13, the recess 35 of the reflecting member 31 and the cover 41.
FIG. 5(b) shows a case where an air layer does not exist in the front
cover 14, that is, the translucent member 32 is formed in the recess 35
of the reflecting member 31 of the front cover 14. The temperature
distribution is represented in contour, temperature t1 is highest, and
temperature becomes low in order of t1, t2, t3, t4, t5 and t6. Besides, a
heat insulating material is disposed at the back surface of the substrate
13 and measurement is performed.

[0065] As shown in FIG. 5(a), if the air layer exists in the front cover
14, the temperature of the substrate 13 becomes high, and the highest
temperature at that time is 80.64° C. This is because, since the
air layer exists in the front cover 14, the heat capacity of the front
cover 14 capable of heat conduction from the substrate 13 is decreased,
and heat radiation from the front surface 14a of the front cover 14 is
reduced.

[0066] As shown in FIG. 5(b), if the air layer does not exist in the front
cover 14, the temperature of the substrate 13 becomes lower than that of
the case where the air layer exists as shown in FIG. 5(a), and the
highest temperature at that time is 69.69° C. This is because,
since the air layer does not exist in the front cover 14, the heat
capacity of the front cover 14 capable of heat conduction from the
substrate 13 is increased, and the heat radiation property from the front
surface 14a of the front cover 14 is improved.

[0067] As stated above, the front cover 14 is brought into surface contact
with the front surface 13a of the substrate 13 without an air layer and
close contact is realized, so that thermal contact is realized, and the
air layer does not exist in the front cover 14. Accordingly, the heat
radiation property from the front surface of the light-emitting device 11
can be improved.

[0068]FIG. 6 and FIG. 7 show a third embodiment. Incidentally, the same
component as that of the foregoing respective embodiments is denoted by
the same reference numeral and its description is omitted.

[0069] As shown in FIG. 6, a light-emitting device 11 is such that in the
light-emitting device 11 of the second embodiment shown in FIG. 4, the
translucent member 32 is not formed in the recess 35 of the reflecting
member 31 of the front cover 14 and an air layer exists, that is, the air
layer exists in the front cover 14 and in a space surrounded by the
substrate 13, the recess 35 of the reflecting member 31, and the cover
41.

[0070] The reflecting member 31 of the front cover 14 is formed of such a
material that the reflectance of the reflecting surface 36 is 80% or
more, and a light shielding angle α of the reflecting surface 36
with respect to the light emitting surface of the semiconductor
light-emitting element 12, which is for preventing glare, is within a
range of 20 to 30°, and more preferably within a range of 25 to
30°.

[0071] The ratio of an area (area of a contact portion between the
reflecting member 31 and the cover 41) of the front surface of the
reflecting member 31 except the portion of the recess 35 to an area of
the recess 35 of the reflecting member 31 at an opening end is regulated
to be within a range of 1:1 to 2:1, so that even if the air layer exists
in the front cover 14, heat radiation property from the front surface of
the light-emitting device 11 can be improved.

[0072]FIG. 7 is a table showing a summary of results obtained by
measuring temperature of the semiconductor light-emitting element 12 (LED
chip) while changing conditions of the front cover 14 of the
light-emitting device 11.

[0073] The conditions include the thickness of the reflecting member 31,
the area ratio of the open area of the reflecting member 31 (area of the
recess 35 of the reflecting member 31 at the open end)/contact area (area
of the contact portion between the reflecting member 31 and the cover
41), the thickness of the cover 41, and the total thickness of the
reflecting member 31 and the cover 41. These conditions are changed, and
the highest temperature of the semiconductor light-emitting element 12
(LED chip) is measured.

[0074] In view of the life and light emission efficiency, the temperature
of the semiconductor light-emitting element 12 (LED chip) is preferably
85° C. or less. Accordingly, if the highest temperature of the
semiconductor light-emitting element 12 (LED chip) is 85° C. or
less, the element is appropriate (OK), and if the temperature exceeds
85° C., the element is inappropriate (NG).

[0075] As a result, the area ratio of the open area of the reflecting
member 31 (area of the recess 35 of the reflecting member 31 at the open
end)/contact area (area of the contact portion between the reflecting
member 31 and the cover 41) is preferably within a range of 35 to 124,
and the total thickness of the reflecting member 31 and the cover 41 is
preferably 6 mm or less.

[0076] With respect to the area ratio of the open area of the reflecting
member 31 (area of the recess 35 of the reflecting member 31 at the open
end)/contact area (area of the contact portion between the reflecting
member 31 and the cover 41), if the area ratio of the recess 35 of the
reflecting member 31 at the open end becomes large, the heat conduction
efficiency from the reflecting member 31 to the cover 41 is reduced, or
the desired light shielding angle α can not be obtained. If the
area ratio of the recess 35 of the reflecting member 31 at the open end
becomes small, the desired light shielding angle α can not be
obtained. Thus, the area ratio of the open area of the reflecting member
31 (area of the recess 35 of the reflecting member 31 at the open
end)/contact area (area of the contact portion between the reflecting
member 31 and the cover 41) is preferably within the range of 35 to 124.

[0077] With respect to the total thickness of the reflecting member 31 and
the cover 41, if the total thickness becomes excessively thick, the
distance of the heat conduction path from the substrate 13 to the front
surface of the cover 41 becomes long and heat conduction can not be
efficiently performed. Accordingly, the total thickness is preferably 6
mm or less. However, if the total thickness becomes smaller than 4 mm,
the heat capacity becomes small, and the heat conduction efficiency from
the substrate 13 to the reflecting member 31 is reduced. Thus, the total
thickness of the reflecting member 31 and the cover 41 is preferably
within the range of 4 to 6 mm.

[0078]FIG. 8 shows a fourth embodiment. Incidentally, the same component
as that of the foregoing respective embodiments is denoted by the same
reference numeral and its description is omitted.

[0079] A front cover 14 includes one cover 43, and the cover 43 is brought
into surface contact, without forming an air layer, with a front surface
13a of a substrate 13 on which a semiconductor light-emitting element 12
is mounted and close contact is realized, so that a thermal contact state
is realized. The cover 43 can be formed by thickly applying a transparent
resin so that the whole front surface 13a of the substrate 13 on which
the semiconductor light-emitting element 12 is mounted is molded. Also in
this case, a nano-fine particle coating 37 may be formed on the front
surface of the cover 43.

[0080] Incidentally, in the case where the semiconductor light-emitting
element 12 is an LED element, not only an SMD (Surface Mount Device)
type, but also a COB (Chip On Board) type may be adopted in which plural
LED chips are directly mounted on a wiring pattern 23 of the front
surface 13a of the substrate 13, and a phosphor layer formed of a
transparent resin mixed with a phosphor is formed to cover the LED chips.

[0081] If the semiconductor light-emitting element 12 is of the COB type,
the phosphor layer is formed by thickly applying the transparent resin
containing phosphor to the front surface 13a of the substrate 13 on which
the plural LED chips are mounted, or the cover 43 is formed such that
each of the LED chips mounted on the substrate 13 is covered with a
phosphor layer in a dome shape, and the transparent resin is thickly
applied to the front surface 13a of the substrate 13.

[0082]FIG. 9 shows a fifth embodiment. Incidentally, the same component
as that of the foregoing respective embodiments is denoted by the same
reference numeral and its description is omitted.

[0083] A front cover 14 includes a reflecting member 31 and a cover 41
arranged on a front surface of the reflecting member 31, and a
translucent member 32 is not formed in a recess 35 of the reflecting
member 31. A wiring pattern 45 for connecting plural semiconductor
light-emitting elements 12 in series is formed on a back surface of the
reflecting member 31.

[0084] The semiconductor light-emitting element 12 includes a pair of
terminals 12a electrically connected to an LED chip, and the terminals
12a are provided to protrude laterally from the semiconductor
light-emitting element 12.

[0085] The semiconductor light-emitting element 12 is inserted from the
back surface of the reflecting member 31 into an opening part 34 of the
reflecting member 31 and is disposed, and the terminals 12a of the
semiconductor light-emitting element 12 are electrically and thermally
connected to and attached to the wiring pattern 45 of the back surface of
the reflecting member 31 by soldering or welding.

[0086] In the light-emitting device 11 constructed as stated above, since
the semiconductor light-emitting element 12 is electrically and thermally
connected to the wiring pattern 45 formed on the back surface of the
front cover 14, a heat conduction path is formed along which heat
generated by the semiconductor light-emitting element 12 is conducted in
order of the wiring pattern 45 and the front cover 14, and the heat is
radiated from the front surface 14a of the front cover 14. Thus, the heat
radiation property from the front surface of the light-emitting device 11
can be improved.

[0087] Next, a sixth embodiment will be described with reference to FIG.
10 to FIG. 20. Incidentally, the same component as that of the foregoing
respective embodiments is denoted by the same reference numeral and its
description is omitted.

[0088] As shown in FIG. 10 to FIG. 12, a light-emitting device 11 includes
plural semiconductor light-emitting elements 12, a substrate 13, phosphor
layers 51 to cover the respective semiconductor light-emitting elements
12, a front cover 14 to cover a front surface 13a of the substrate 13,
and a heat conduction layer 52 intervening between the substrate 13 and
the front cover 14.

[0089] The substrate 13 is formed into a substantially square shape. The
substrate 13 is an insulating member and is formed of glass epoxy resin
of synthetic resin material having low heat conductivity. Ceramic
material or other synthetic resin material can also be used for the
substrate 13. Incidentally, although the substrate 13 is preferably made
of a material having low heat conductivity, a material having high heat
conductivity, such as aluminum, may be used.

[0090] A wiring pattern 23 is formed on the front surface 13a of the
substrate 13. As shown in FIG. 10 (FIG. 14), the wiring pattern 23
includes substantially hexagonal mounting pads 23a on which the
respective semiconductor light-emitting elements 12 are disposed, feeding
conductors 23b having a specific pattern to electrically connect the
mounting pads 23a, and feeding terminals 23c. The plural mounting pads
23a are arranged in a matrix so as to be formed in plural lines, and
specifically, 8 mounting pads×6 lines, that is, 48 mounting pads in
total are formed.

[0091] As shown in FIG. 12, the wiring pattern 23 has a three-layer
structure, and a copper pattern as a first layer 231 is provided by
etching on the front surface of a substrate body 21 of the substrate 13.
A second layer 232 is provided on the first layer 231 by electrolytic
plating of nickel (Ni), and a third layer 233 is provided on the second
layer 232 by electrolytic plating of silver (Ag). The third layer 233 of
the wiring pattern 23, that is, the surface layer is plated with silver
(Ag), and the total light beam reflectance is as high as 90% or more.

[0092] Besides, the semiconductor light-emitting element 12 is made of an
LED bare chip. As the LED bare chip, for example, one to emit blue light
is used in order to cause a light emitting part to emit white light. The
LED bare chip is bonded onto the mounting pad 23a by using a silicone
resin insulating adhesive 54. The plural semiconductor light-emitting
elements 12 are arranged in a matrix so as to be mounted in plural lines,
and specifically, 8 elements×6 lines, that is, 48 elements in total
are mounted.

[0093] The LED bare chip is, for example, an InGaN element, and a
light-emitting layer is laminated on a translucent sapphire element
substrate. The light-emitting layer is formed by sequentially laminating
an n-type nitride semiconductor layer, an InGaN light-emitting layer and
a p-type nitride semiconductor layer. An electrode for applying current
to the light emitting layer includes a plus side electrode formed of a
p-type electrode pad on the p-type nitride semiconductor layer and a
minus side electrode formed of an n-type electrode pad on the n-type
nitride semiconductor layer. These electrodes are electrically connected
onto the wiring pattern 23 by a bonding wire 55. The bonding wire 55 is
made of a gold (Au) thin wire, and is connected through a bump containing
gold (Au) as its main ingredient in order to improve mounting strength
and to reduce damage of the LED bare chip.

[0094] Besides, the phosphor layer 51 is made of a translucent synthetic
resin, for example, a transparent silicone resin, and contains an
appropriate amount of phosphor. The phosphor layer 51 has a conical side
shape and is formed in an arc convex shape, and individually covers and
seals the semiconductor light-emitting element 12 and the bonding wire
55. The phosphor is excited by light emitted by the semiconductor
light-emitting element 12, and emits light of color different from the
color of the light emitted by the semiconductor light-emitting element
12. If the semiconductor light-emitting element 12 emits blue light, in
order to enable white light to be emitted, a yellow phosphor to emit a
yellow light complementary to the blue light is used as the phosphor. The
phosphor layer 51 is formed such that the resin in an unhardened state is
applied correspondingly to the respective semiconductor light-emitting
elements 12 and the bonding wires 55, and then is hardened by heat
hardening or by being left for a specified time.

[0095] Besides, as shown in FIG. 10 to FIG. 13, the front cover 14 covers
the whole area of the front surface 13a of the substrate 13 including the
phosphor layer 51, has a translucent property, and is molded into a
substantially square dish shape by transparent acryl resin or
polycarbonate resin. A receiving recess 14c to receive the substrate 13
is formed on the back surface 14b of the front cover 14, and air layer
forming units 56 opposite to the respective semiconductor light-emitting
elements 12 and the respective phosphor layers 51 are formed on the back
surface of the receiving recess 14c. That is, the plural air layer
forming units 56 are arranged in a matrix so as to be formed in plural
line, and specifically, 8 units×6 lines, that is, 48 units in total
are formed. The respective air layer forming units 56 are formed of
conical recesses to receive the respective semiconductor light-emitting
elements 12 and the phosphor layers 51, and includes circular opening
parts 56a opening on the back surface of the receiving recess 14c.
Incidentally, the air layer forming units 56 may be formed of members
different from the front cover 14, and the members may be provided on the
front cover 14.

[0096] A flange 14d protruding outward is formed on a peripheral part of
the front cover 14. The flange 14d functions as an attachment part when
the light-emitting device 11 is attached to an attachment target part,
such as a body of a lighting apparatus or a base, by a screw 14e as a
fixing unit.

[0097] A heat insulating layer 57 is formed on the back surface of the
substrate 13 combined with the front cover 14. The heat insulating layer
57 is constructed to form an air layer between the back surface of the
substrate 13 and the attachment target part. That is, a specified
interval is provided between the back surface of the substrate 13 and the
attachment target part Specifically, the specified interval is provided
between the back surface of the substrate 13 and the attachment target
part by the depth size of the receiving recess 14c and an attachment
screw 58 to fix the substrate 13 to a specified position, and the heat
insulating layer 57 is formed. Accordingly, the receiving recess 14c and
the attachment screw 58 constitute a heat insulating layer forming unit.
Incidentally, the heat insulating layer 57 is not limited to the air
layer, and may be formed by, for example, disposing a heat insulating
material in the portion of the air layer.

[0098] Besides, as shown in FIG. 11 and FIG. 12, the heat conduction layer
52 is closely provided without a gap between the front surface 13a of the
substrate 13 and the back surface 14b of the front cover 14, that is, the
back surface of the receiving recess 14c, and is made of a transparent
silicone adhesive having adhesiveness. That is, the heat conduction layer
52 functions as an adhesive to fix the substrate 13 to the receiving
recess 14c of the front cover 14.

[0099] Specifically, the heat conduction layer 52 is provided over
substantially the whole area between the front surface 13a of the
substrate 13 and the area of the front cover 14 except for the air layer
forming unit 56. Accordingly, the substrate 13 is certainly attached to
the front cover 14 by the heat conduction layer 52 and the attachment
screw 58.

[0100] Incidentally, the heat conduction layer 52 is not limited to the
silicone adhesive, and an adhesive of another material such as epoxy
resin can be used. Further, although the heat conduction layer 52
preferably has the adhesiveness, the adhesiveness is not necessarily
required as long as the material is closely provided between the front
surface 13a of the substrate 13 and the back surface 14b of the front
cover 14 and can made the heat conduction thereof excellent.

[0101] As stated above, in the state where the substrate 13 is attached to
the front cover 14, conical air layers 59 are formed between the front
surface 13a of the substrate 13 and the air layer forming units 56
opposite to the respective semiconductor light-emitting elements 12.

[0102] Next, the light-emitting device 11 of the sixth embodiment
constructed as stated above, together with the outline of a manufacturing
process, will be described with reference to FIG. 13 to FIG. 18.

[0103] As shown in FIG. 13, the air layer forming units 56 made of conical
recesses are arranged in a matrix and are formed on the front cover 14.

[0104] As shown in FIG. 14, the wiring pattern 23 is formed on the front
surface 13a of the substrate 13. The wiring pattern 23 includes the
mounting pads 23a, the feeding conductors 23b, and the feeding terminals
23c. On the side of one side of the hexagonal shape of the mounting pad
23a, a feeding conductor part 23b1 having thin width for bonding wire
connection is extended in a direction perpendicular to this side.
Besides, on the side of the other side, a cut 23a1 for insulation is
formed in which the feeding conductor part 23b1 for bonding wire
connection of the adjacent mounting pad 23a enters and is disposed. The
feeding conductor part 23b1 for bonding wire connection and the cut 23a1
have such a positional relation that they do not contact with each other,
and the feeding conductor part 23b1 and the adjacent mounting pad 23a are
in an electrically insulated state. In such positional relation, the
plural mounting pads 23a are arranged in a matrix.

[0105] The mounting pads 23a are formed on the surface of the substrate 13
in plural lines (6 lines), and the lines are mutually electrically
connected by the feeding conductors 23b. Incidentally, although such a
state occurs that the adjacent mounting pads 23a are connected by the
feeding conductor 23b, a through-hole 13b passing through the substrate
13 is formed in an intermediate part of the feeding conductor 23b, and
the feeding conductor 23b is cut with the through-hole 13b, and the
adjacent mounting pads 23a are electrically shielded.

[0106] The feeding terminals 23c are the feeding terminals at the positive
pole and the negative pole, and are connected to the feeding conductors
23b at the right and left both end sides. The feeding terminal 23c is
connected with a lead wire by soldering or the like, and power is
supplied from a not-shown power supply circuit.

[0107] As shown in FIG. 15, the plural semiconductor light-emitting
elements 12 are mounted on the mounting pads 23a of the wiring pattern 23
formed as stated above, and the phosphor layers 51 are formed so as to
cover the semiconductor light-emitting elements 12. The plus side
electrode and the minus side electrode of each of the semiconductor
light-emitting elements 12 are respectively connected to the mounting pad
23a and the feeding conductor part 23b1 of the adjacent mounting pad 23a
by the bonding wires 55. Accordingly, two series circuits in which the
plural semiconductor light-emitting elements 12 are connected while the
feeding terminals 23c at the positive pole side and the negative pole
side are connection points, are connected in parallel. That is, in FIG.
15, the semiconductor light-emitting elements 12 of the upper three lines
are connected in series, and the semiconductor light-emitting elements 12
of the lower three lines are connected in series, and the two series
circuits are connected in parallel to the power supply.

[0108] The phosphor layers 51 are applied so as to cover the respective
semiconductor light-emitting elements 12 and the bonding wires 55. At
this application, the application is performed in an unhardened state,
and then, hardening is performed by heat hardening or by being left for a
specified time and hardened.

[0109] Next, as shown in FIG. 16, the receiving recess 14c of the front
cover 14 is turned upward, and the transparent silicone adhesive which
forms the heat conduction layer 52 is applied to the back surface of the
receiving recess 14c except for the areas of the opening parts 56a of the
air layer forming units 56. Next, the substrate 13 shown in FIG. 15 is
disposed in the receiving recess 14c of the front cover 14 from above,
and the attachment screw 58 is screwed into the front cover 14 through
the substrate 13, so that the substrate 13 is attached to the front cover
14. In the state where the substrate 13 is disposed in the receiving
recess 14c of the front cover 14, the heat conduction layer 52 is closely
provided without a gap between the front surface 13a of the substrate 13
and the back surface 14b of the front cover 14, and bonds these.

[0110] As shown in FIG. 17, when the substrate 13 and the front cover 14
are combined, the respective air layer forming units 56 faces the
respective semiconductor light-emitting elements 12 and the phosphor
layers 51, and form the air layers 59. In this case, as shown in FIG. 18,
although the opening part 56a of the air layer forming unit 56 is formed
to be larger than the phosphor layer 51, the opening part is formed to be
smaller than the hexagonal mounting pad 23a. In other words, the mounting
pad 23a extends to the outside of the area of the opening part 56a of the
air layer forming unit 56. Accordingly, the heat conduction layer 52 is
applied to an extension part 23d extending from the mounting pad 23a and
is disposed to contact therewith. Thus, heat conduction is performed from
the mounting pad 23a to the front cover 14 through the heat conduction
layer 52.

[0111] Next, a lighting apparatus 61 using the light-emitting device 11
will be described with reference to FIG. 19 and FIG. 20. The lighting
apparatus 61 is attached to a ceiling 62 and is used, and includes an
apparatus body 63 and plural light-emitting devices 11 disposed on the
apparatus body 63. The apparatus body 63 is made of, for example,
aluminum, and is formed to be substantially rectangular. The
light-emitting devices 11 are fixed to the apparatus body 63 by screwing
or the like, while the apparatus body 63 is attached to the ceiling 63 by
a fixing unit such as a bolt. Besides, a power supply unit incorporating
a not-shown power supply circuit is connected to the light-emitting
devices 11. Incidentally, the number of the light-emitting devices 11 is
suitably selected and the devices can be disposed.

[0112] Next, the operation of the light-emitting device 11 of the sixth
embodiment will be described.

[0113] When the power supply circuit of the power supply unit supplies
power to the respective light-emitting devices 11, the respective
semiconductor light-emitting elements 12 of the respective light-emitting
devices 11 emit light concurrently, and the respective light-emitting
devices 11 are used as planar light sources to emit white light.

[0114] During light emission of the semiconductor light-emitting elements
12, the mounting pads 23a function as heat spreaders to diffuse heat
generated by the respective semiconductor light-emitting elements 12.
Further, during light emission of the semiconductor light-emitting
elements 12, light directed to the substrate 13 in the light emitted by
the semiconductor light-emitting element 12 is reflected by the surface
layer of the mounting pad 23a to the forward direction as the use
direction of light mainly.

[0115] The air layer forming units 56 are provided to face the respective
semiconductor light-emitting elements 12, and the air layers 59 are
formed thereby. Thus, as shown in FIG. 12, the light emitted from each of
the semiconductor light-emitting elements 12 is diffused at the interface
between the air layer 59 and the front cover 14, and is irradiated
forward from the front surface 14a of the front cover 14. Accordingly,
the brightness of the light irradiated from the front cover 14 of the
light-emitting device 11 is uniformed, and uneven brightness can be
suppressed, and further, reduction of extraction efficiency of light from
the semiconductor light-emitting element 12 can be suppressed.

[0116] During light emission of the respective semiconductor
light-emitting elements 12, heat is generated from the semiconductor
light-emitting elements 12, and the heat is mainly conducted from the
semiconductor light-emitting element 12 to the substrate 13, the heat
conduction layer 52 and the front cover 14 and is radiated. That is, the
heat from the semiconductor light-emitting element 12 is conducted to the
front surface of the light-emitting device 11 and is radiated. This is
because the heat conduction layer 52 is closely provided between the
substrate 13 and the front cover 14, and the heat resistance is reduced.
Accordingly, the heat from the semiconductor light-emitting element 12 is
conducted to the front cover 14, the heat conduction to the back surface
of the substrate 13 is suppressed, and the heat conducted to the ceiling
62 or the like is reduced.

[0117] Especially, since the heat conduction layer 52 is disposed to
contact the mounting pad 23a, the heat from the semiconductor
light-emitting element 12 is efficiently conducted from the mounting pad
23a to the heat conduction layer 52, and further is conducted to the
front cover 14 and is radiated.

[0118] Besides, since the heat conduction layer 52 has adhesiveness, and
is used also as an adhesive between the substrate 13 and the front cover
14, the structure can be simplified. Further, since the substrate 13 and
the front cover 14 are bonded by the heat conduction layer 52, dust does
not enter between the substrate 13 and the front cover 14, contamination
hardly occurs, and water-proof function can also be realized.

[0119] Besides, the substrate 13 is formed of a glass epoxy resin having
low heat conductivity, and the heat insulating layer 57 is formed on the
back surface of the substrate 13. Accordingly, heat conduction to the
back surface of the light-emitting device 11 is suppressed, and heat
conduction to the front surface of the light-emitting device 11 can be
accelerated.

[0120] Further, since the light-emitting device 11 includes the front
cover 14, a front cover for the lighting apparatus 61 is not required to
be provided, and the structure can be simplified.

[0121] Besides, the phosphor layers 51 are applied so as to individually
cover the respective semiconductor light-emitting elements 12 and the
bonding wires 55, the amount of phosphor contained in the phosphor layers
51 can be reduced, and advantage is obtained in cost.

[0122] As described above, according to the sixth embodiment, the
light-emitting device 11 can be provided in which the heat generated from
the semiconductor light-emitting elements 12 can be conducted to the
front surface of the light-emitting device 11, the light from the
semiconductor light-emitting elements 12 is uniformed, the uneven
brightness can be suppressed, and the reduction of extracting efficiency
of the light from the semiconductor light-emitting elements 12 can be
suppressed, and the lighting apparatus 61 using the light-emitting device
11 can be provided.

[0123] Next, a seventh embodiment will be described with reference to FIG.
21. Incidentally, the same component as that of the foregoing respective
embodiments is denoted by the same reference numeral, and its description
is omitted.

[0124] In the embodiment, a lighting apparatus 61 of a ceiling mounting
type is described which is installed on a ceiling 62 and is used. The
lighting apparatus 61 includes an apparatus body 63 which is thin and
long and has a substantially parallelepiped shape, and plural
light-emitting devices 11 are linearly disposed in the apparatus body 63.
Besides, a power supply unit is incorporated in the apparatus body 63.
Incidentally, a front cover for the lighting apparatus 61 is not provided
at a lower opening part of the apparatus body 63.

[0125] According to this embodiment, the lighting apparatus 61 can be
provided in which heat generated from semiconductor light-emitting
elements 12 can be conducted to the front surface of the light-emitting
device 11, heat conducted to the ceiling 62 can be reduced, and uneven
brightness can be suppressed.

[0126] Next, an eighth embodiment will be described with reference to FIG.
22. Incidentally, the same component as that of the foregoing respective
embodiments is denoted by the same reference numeral and its description
is omitted.

[0127] In this embodiment, a material of transparent silicone resin having
specified viscosity and fluidity is used for a heat conduction layer 52.
After the transparent silicone resin is applied to substantially the
whole area of a front surface 13a of a substrate 13 including respective
phosphor layers 51 covering respective semiconductor light-emitting
elements 12, the front surface 13a of the substrate 13 is covered with a
front cover 14, and a light-emitting device 11 is constructed.
Incidentally, although the heat conduction layer 52 preferably has
adhesiveness, the adhesiveness is not necessary required as long as heat
conduction can be secured.

[0128] Also in this embodiment, the same effect as the foregoing
respective embodiments can be obtained.

[0129] Next, a ninth embodiment will be described with reference to FIG.
23. Incidentally, the same component as that of the foregoing respective
embodiments is denoted by the same reference numeral and its description
is omitted.

[0130] In this embodiment, a size of an opening part 56a of an air layer
forming unit 56 is changed.

[0131] That is, the size of the opening part 56a of the air layer forming
unit 56 is set to be larger than that in the sixth embodiment (see FIG.
18). By this, since the air layer forming unit 56 becomes large, the
diffusion effect of light of a semiconductor light-emitting element 12
can be raised.

[0132] Accordingly, by setting the size of the opening part 56a, an
adjustment can be made as to whether importance is given to the heat
radiation effect of heat generated by the semiconductor light-emitting
element 12 or the diffusion effect of light of the semiconductor
light-emitting element 12.

[0133] Next, a tenth embodiment will be described with reference to FIG.
24. Incidentally, the same component as that of the foregoing respective
embodiments is denoted by the same reference numeral and its description
is omitted.

[0134] In this embodiment, the shape of an air layer forming unit 56 is
changed and the shape of an air layer 59 is changed.

[0135] In this embodiment, the air layer forming unit 56 is formed in a
truncated cone shaped recess.

[0136] Also when the air layer 59 is formed by the air layer forming unit
56, light from a semiconductor light-emitting element 12 can be diffused
and uneven brightness can be suppressed. As stated above, the shape of
the air layer forming unit 56 can be suitably selected.

[0137] Next, an eleventh embodiment will be described with reference to
FIG. 25. Incidentally, the same component as that of the foregoing
respective embodiments is denoted by the same reference numeral and its
description is omitted.

[0138] In this embodiment, the shape of an air layer forming unit 56 is
changed and the shape of an air layer 59 is changed.

[0139] In this embodiment, the air layer forming unit 56 is formed in a
dome-shaped recess.

[0140] Also when the air layer 59 is formed by the air layer forming unit
56, light from a semiconductor light-emitting element 12 can be diffused,
and uneven brightness can be suppressed. As stated above, the shape of
the air layer forming unit 56 can be suitably selected.

[0141] Next, a twelfth embodiment will be described with reference to FIG.
26. Incidentally, the same component as that of the foregoing respective
embodiments is denoted by the same reference numeral and its description
is omitted.

[0142] In this embodiment, concave-convex parts 14f are formed on a back
surface of a receiving recess 14c of a front cover 14. The concave-convex
parts 14f are formed to be positioned between semiconductor
light-emitting elements 12.

[0143] Accordingly, when light emitted from the semiconductor
light-emitting elements 12 and light reflected by mounting pads 23a are
irradiated to the concave-convex parts 14f, those lights are diffused and
irradiated outward, and in cooperation with the action of an air layer
59, uneven brightness of a light-emitting device 11 can be efficiently
suppressed.

[0144] Incidentally, the mounting pad 23a may not be used as the wiring
pattern 23. That is, if heat conduction is obtained, the mounting pad is
not necessarily required to be electrically connected, and there is a
case where it is sufficient if function as a heat spreader is provided.

[0145] Besides, the air layer forming unit 56 has only to form the air
layer 59 for diffusing light emitted from the semiconductor
light-emitting element 12, and its shape, size and the like are not
limited.

[0146] Besides, the heat conduction layer 52 may be provided in the whole
area or partially between the front surface 13a of the substrate 13 and
the area of the front cover 14 except for the air layer forming unit 56.
Besides, "the heat conduction layer disposed so as to contact the
mounting pad" means a mode in which heat is conducted from the mounting
pad 23a to the heat conduction layer 52.

[0147] Besides, the light-emitting part may be constructed such that, for
example, phosphor is not used, and the semiconductor light-emitting
element 12 directly emits red light, green light or blue light.

[0148] A diffusion agent such as alumina or silica may be mixed in the
front cover 14 so that the diffusion effect is raised.

[0149] As the semiconductor light-emitting element, not only the LED
element, but also an EL (Electro Luminescence) element may be used.

[0150] The lighting apparatus may be a bulb-type light source, a lighting
equipment used outdoor or indoor, a display device or the like.

[0151] While certain embodiments of the invention have been described,
these embodiments have been presented by way of example only, and are not
intended to limit the scope of the invention. The novel embodiments may
be embodied in a variety of other forms, and various omissions,
substitutions and changes may be made without departing from the gist of
the invention. These embodiments and modifications thereof fall within
the scope and gist of the invention and within the scope of the invention
recited in the claims and their equivalents.